Data storage and retrieval system with parameterized category definitions for families of categories and dynamically generated search indices

ABSTRACT

A data storage and retrieval system with parameterized category definitions and dynamically generated search indices. A parameterized category definition for a family of categories is obtained consisting of a parameterized predicate, such that parameter values can be provided with a search query to identify information items that match a category within the family of categories. The parameterized category definition is divided into a parameterized part and a static part. The static part is used to create associations between information items and the family of categories. The disclosed system processes the parameterized part of the category family definition to dynamically generate one or more search indices. The disclosed system determines whether any existing indices match the parameters of the parameterized part, and can accordingly be re-used. In the case where one or more indices are missing that are needed to support the parameterized part of the category family definition, the disclosed system operates to create them based on information items associated with the family of categories based on the static part of the parameterized category definition. Queries supplying values for the parameters of the parameterized category definition for the family of categories are subsequently processed to identify information items belonging to specific, dynamically defined categories within the family of categories.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation in Part under 35 U.S.C. 120 ofprior application Ser. No. 11/039,191, entitled “Data Storage andRetrieval System with Intensional Category Representations to ProvideDynamic Categorization of Information Items”, filed Jan. 20, 2005, alldisclosures of which are hereby included by reference herein.

FIELD OF THE INVENTION

The present invention relates generally to data storage and retrievalsystems, and more specifically to a data storage and retrieval systemwith parameterized category families and dynamically generated searchindices.

BACKGROUND OF THE INVENTION

As it is generally known, in the area of computer programs, manyspecific types of data storage and retrieval systems are currentlyavailable. For example, a database is a collection of information thatis organized so that it can be conveniently accessed, managed, andupdated. Databases are sometimes classified according to theirorganizational approach. The most prevalent approach is the relationaldatabase, a tabular database in which data is defined so that it can bereorganized and accessed in a number of different ways. A distributeddatabase is one that can be dispersed or replicated among differentpoints in a network. An object-oriented programming database is one thatis congruent with the data defined in object classes and subclasses.Other specific types of databases are also available. A database manageroften provides computer system users with the ability to controlread/write access, specify report generation, and analyze usage. SQL(Structured Query Language) is an example of a standard language formaking interactive queries from and updating a database.

In any specific type of data storage and retrieval system, it maysometimes be desirable to organize data items into categories. It mayfurther be desirable that such categories be associated with categorydefinitions of some kind or type. If information items are appropriatelyorganized based on such definitions, system performance may be improvedby such techniques as indexing of the information items, to providesearch index data structures that improve the performance of searchoperations. However, due to their specific nature, not all categories ofinformation items may be considered closed ended for purposes ofdefinition, and therefore are not amenable to static categorydefinitions.

For example, where there may be a need to provide category definitionsfor information item categories such as those representing or associatedwith appointments ranging over specific time periods. Such a situationmay arise when categories would be helpful in determining appointmentinformation items associated with any specific day, week, month, year,or other period of time. However, it may not be feasible to provide anexhaustive set of category definitions corresponding to all possibletime periods. A solution in which discrete category definitions areestablished and maintained for every possible interval of time wouldresult in an excessively high number of appointment categories.Alternatively, a limited number of such static category definitions mayresult in a system that is overly restrictive with respect todetermining and/or collecting appointment information.

For the above reasons and others, it would be desirable to have a newsystem for information item categorization that does not rely onexhaustively defining all possible categories that may be needed. Thenew system should further allow for category definitions that canadvantageously be used to provide improved system performance, such asthrough effective and efficient indexing of information items withregard to the category definitions.

SUMMARY OF THE INVENTION

To address the above described needs and others, a data storage andretrieval system with parameterized category definitions and dynamicallygenerated search indices is disclosed. In the disclosed system, aparameterized category definition is obtained that defines a family ofcategories, for example from an application program or user. Theparameterized category definition consists of a parameterized predicate,which may be embodied as a software routine or software routine with aBoolean result. When parameter values are provided to a parameterizedcategory definition, a category of information items can be identifiedthat reflects those values. When supplied with such parameter values,the parameterized predicate for a family of categories provides a testfor an information item to which the predicate is applied, the result ofwhich indicates whether that information item is a member of a categorywithin the family of categories that is dynamically defined by theparameter values.

The parameterized category definition for a family of categories may beconverted into a conjunctive normal form logical representation or thelike for convenient processing. Using such a logical representation, theparameterized category definition may then be divided into aparameterized part and a static part. The static part is used to createassociations between information items and the family of categoriesdefined by the parameterized category definition. The disclosed systemprocesses the parameterized part of the parameterized categorydefinition by analyzing it, and then searching for any existing indicesthat match the parameters of the parameterized part. If any suchexisting indices are located, they are re-used to support theparameterized part of the parameterized category definition. In the casewhere one or more indices are missing that are needed to support theparameterized part of the parameterized category definition, thedisclosed system operates to create them. Such newly created indicesmay, for example, be created across those information items associatedwith the static part of the parameterized category definition. Thedisclosed system thus operates to index stored information items toassociate them with the static and parameterized portions of theparameterized category definition, in order to effectively andefficiently establish associations between information items and theassociated family of categories.

During query processing, the disclosed system obtains a search queryidentifying a family of categories corresponding to a previouslyobtained parameterized category definition, and parameter valuesdefining a category within that family of categories. The parametervalues and previously established indices for the parameterized portionof the parameterized category definition are used to determine the setof information items in a “virtual category” of information items withinthe family of categories. The set of information items in the virtualcategory may then be reduced based on other conditions in the searchquery in order to produce the search results.

Thus there is disclosed a new system for information item categorizationthat does not rely on exhaustively defining all possible categories thatmay be needed. The new system further allows for parameterized categorydefinitions that can advantageously be used to provide improved systemperformance through effective and efficient indexing of informationitems.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to facilitate a fuller understanding of the present invention,reference is now made to the appended drawings. These drawings shouldnot be construed as limiting the present invention, but are intended tobe exemplary only.

FIG. 1 is a block diagram illustrating components of an illustrativeembodiment;

FIG. 2 is a flow chart illustrating steps performed to accomplishregistration of categories in an illustrative embodiment; and

FIG. 3 is a flow chart illustrating steps performed to process a queryincluding an indication of a family of categories in an illustrativeembodiment.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

As shown in FIG. 1, software components in an illustrative embodiment ofthe disclosed system include a data storage and retrieval kernel 12executing on at least one computer system 10. The data storage andretrieval kernel 12 is shown including an information item and categorycreation and modification interface 14 and an information retrievalinterface 16. The interfaces 14 and 16 are accessible, for example, byway of application program interfaces (APIs), to one or more applicationprograms, shown for purposes of illustration as applications 18including applications 18 a, 18 b, 18 c, etc. The computer system 10 mayinclude at least one processor, program storage, such as memory, forstoring program code executable on the processor, and one or moreinput/output devices and/or interfaces, such as data communicationand/or peripheral devices and/or interfaces. The computer system 10 mayfurther be embodied as one or more physically distributed computersystems, such as one or more client and server computer systems, thatare communicably connected by a data communication system, such as aLocal Area Network (LAN), the Internet, or the like. The computer system10 may further include appropriate operating system software.

As further shown in FIG. 1, the data storage and retrieval kernel 12includes a number of information items 20, a number of categorydefinitions 24, and a number of automatically pre-computed categorymembership data structures 22. In a preferred embodiment, theinformation items 20 and category definitions 24 are stored separately,in that they are logically independent, and the category definitions 24maintain no references (e.g. pointers) to or identifications (e.g.names) of the information items they designate as members of therespective categories that they define.

Advantageously, the structures of specific information items withininformation items 20 may be highly variable. First, different ones ofthe information items 20 may include different numbers of propertieshaving associated values. Thus the information items 20 may each havedifferent numbers of properties. Additionally, the number of propertiesfor a given one of the information items 20 may change over time.Information items in a preferred embodiment include some number ofproperties, each of which has a corresponding value. Values ofinformation item properties may also change dynamically.

The information items 20 may include any specific types of information.In one embodiment, the information items 20 include personal informationmaintained by individuals themselves during and/or for their general,daily, and/or professional activities, and the properties of each of theinformation items 20 may accordingly include corresponding personalinformation properties. Such personal information properties may, forexample, include various types of contact information, such as postaladdresses, electronic mail addresses, telephone numbers, persons' names,and any other type of contact information. Personal informationproperties may further include information regarding personalactivities, to do lists, schedule information including appointmentdates and times, and any other type of personal information. Thepreceding examples of personal information properties are given only forpurposes of explanation, and the disclosed system is not so limited.Accordingly, the disclosed system may be implemented in embodimentsusing any other specific type of personal information, or any othernon-personal information.

The category definitions 24 may be provided by applications 18 at runtime. Each of the category definitions 24 consists of, includes or isassociated with a predicate, which may be embodied as a software routineor software routine with a Boolean result. The predicate for a categoryprovides a test for an information item to which the predicate isapplied. If an information item passes the test defined by the predicateof a category, then the information item is considered to be containedwithin the category, and an association may be formed between theinformation item and the category. In one embodiment, the disclosedsystem uses “intensional” category assignment, in that each categoryincludes a predicate which, applied to an information item, logicallyreturns true or false with respect to whether the information itembelongs in that category. This approach is distinct from previous“extensional” approaches, which rely on information item identities andcategories that include the information item lists. In traditionalrelational databases, only extensional categorization has beensupported, represented by the table membership of the records in thedatabase. Such existing systems have not supported testing of thecontents of a record to determine which table it belongs to.

General definitions for “intensional definition” may be found in varioussources. In the area of logic, an intensional definition gives themeaning of a term by giving all the properties required for something tofall under that definition—the necessary and sufficient conditions forbelonging to a set being defined. One example of an intensionaldefinition of “bachelor” is “unmarried man.” This is because being anunmarried man is an essential property of something referred to as abachelor. Being an unmarried man is a necessary condition of being abachelor—one cannot be a bachelor without being an unmarried man. Beingan unmarried man is also a sufficient condition of being a bachelor—anyunmarried man is a bachelor. The intensional definition approach isopposite to the extensional definition approach, which defines bylisting everything falling under a definition. Accordingly, anextensional definition of “bachelor” would be a listing of all theunmarried men in the world. In this regard, intensional definitions arebest used when something has a clearly-defined set of properties, andwork well for sets that are too large to list in an extensionaldefinition. Moreover, it is impossible to give an extensional definitionfor an infinite set, but an intensional one can often be statedconcisely. For example, while the infinite number of even numbers makesthem impossible to list, they can be defined intensionally by sayingthat even numbers are integer multiples of two.

The predicates used in the category assignment process of the disclosedsystem advantageously provide intensional definitions for correspondingcategories. Accordingly, each predicate of the disclosed system teststhe properties of an information item to determine if that informationitem belongs to the category defined by the predicate. The intensionaldefinition of categories in the disclosed system enables categorizationof information items at run time, and accordingly allows informationitems to dynamically change their categorical membership. The disclosedsystem may operate to check information items at any time to determinewhether they have changed category membership. Each category mustaccordingly at least include a category name and a predicate which canbe applied to an information item to determine if the information itembelongs to the category.

In the disclosed system, the category definitions 24 may include staticpredicates defining static categories, as well as parameterizedpredicates defining families of categories. Such parameterizedpredicates are examples of parameterized category definitions. In thecase of a family of categories defined by a parameterized categorydefinition, the categories contained within the family are defined whenspecific parameter values are provided at run time for the parameterizedportion of the parameterized predicate. The predicates in the categorydefinitions 24 of FIG. 1 are shown including a static predicate 24 a, astatic predicate 24 b, and a parameterized predicate 24 c. Theparameterized predicate 24 c is shown including a static part 26, aswell as a parameterized part 28. Those skilled in the art will recognizethat the disclosed system may be embodied using any specific number ofcategory definitions.

The predicates for the category definitions 24 may each be satisfied bya different set of the information items 20. If one of the informationitems 20 satisfies any one of the predicates defining a category, it maybe considered as belonging to the corresponding category for anyprocessing or handling that might be associated with that correspondingcategory at any point during the processing of that information item.Additionally, if one of the information items 20 satisfies a predicatedefining a category, then that information item can be included when allthe members of the category are enumerated or otherwise processed at anypoint.

In the case of a parameterized predicate, such as predicate 24 c, anydetermination of category membership for a given information item mustbe based in part on parameter values for the parameterized part 28. Thuscategories of information items within a family of categories can bedynamically defined as needed at run time by combining the parameterizedpredicate for the family of categories with parameter values for theparameterized part of the parameterized predicate.

Automatically pre-computed category membership data structures 22 may beused to support information item retrieval operations performed throughthe information item retrieval interface 16, in order to provide betterresponse times for queries, including those queries that may usecategory names or definitions as part of the query. In a preferredembodiment, the data structures 22 include one or more search index datastructures that associate category names with ones of the informationitems 20 belonging to the corresponding categories. Such index datastructures may be populated with information items by automaticallyapplying predicates within the category definitions 24 to theinformation items 20, so that when a query is received indicating acategory name, the members of that category within the information items20 can be quickly identified using the index data structures.

In the case of a family of categories, indexing of the information items20 can be performed in the same way, initially based on the staticportion of the parameterized predicate. Thus the static portion of theparameterized category definition can be used to identify thoseinformation items that match the static portion of the parameterizedcategory definition. Such information items are then associated with thefamily of categories for the parameterized category definition, and suchassociations maintained in the pre-computed category membership datastructures 22. However, indexing based on the parameterized part ishandled differently. As further described below, when a category familydefinition is obtained, the disclosed system analysis the parameterizedpart of the parameterized predicate. Based on this analysis, thedisclosed system searches for an existing index that identifiesinformation items within information items 20 having properties matchingthe parameterized part of the parameterized predicate.

For example, in the case where a family of categories is defined formeetings, a parameterized portion of the parameterized predicatedefining it might include start time and end time parameters. Similarly,a family of categories might be defined for conference calls havingstart and end time parameters in a parameterized portion of itsparameterized predicate. Another family of categories might also bedefined for appointments, also having start and end time parameters inthe parameterized part of its parameterized predicate, and so on. Allsuch families of categories having start and end time parameters intheir definitions can share an index structure within the automaticallypre-computed category membership data structures 22 mapping specificvalues of those start and end time parameters to matching informationitems. In this example, the shared index structure would map specificstart and end times to matching information items. Such a shared indexmay then be used in combination with index entries in the datastructures 22 that are pre-computed based on the static parts of theparameterized predicates for the families of categories, in order toquickly identify information items that are members of dynamicallydefined categories within the families of categories.

In the case where there is no matching index for the parameterized partof a parameterized category definition, the disclosed system may operateto create an index for the parameterized part. Such an index for aparameterized part of a parameterized category definition may, forexample, be created across those information items matching the staticpart of the same parameterized category definition, and stored in thedata structures 22.

The data structures 22 may be created or modified automatically,synchronously or asynchronously, in response to the items or categoriesbeing created or modified via the information and category creation andmodification interface 14. The information item and category creationand modification interface 14 also permits information items 20 to becreated and/or modified dynamically, and independently permitscategories to be created dynamically through the category definitions24. The interface 14 may be embodied to allow information item creationand/or modification operations to be performed directly or indirectly bya user, for example in an embodiment where the disclosed system storespersonal information for that user. Such user controlled actions may,for example, be provided through a graphical user interface (GUI) or thelike associated with or provided by the interface 14, and/or provided byone of the applications 18. The interface 14 may also or alternativelyallow information item creation and/or modification by software programsand/or processes external to the data storage and retrieval kernel 12.Such actions may, for example, be provided through an applicationprogramming interface (API) or the like associated with or provided bythe interface 14.

In a preferred embodiment, item modifications are provided in twodifferent ways, depending on how categories are configured. Synchronouscategories require that item modification operations are reflectedimmediately in the results of any subsequent information retrievaloperations. In this way, a category can be configured such that when anitem modification affecting the membership of that category returns acompletion status, all subsequent queries will return results thatcompletely reflect that modification. Asynchronous categories do notrequire immediate consistency with the modifications in subsequentinformation retrieval operations.

The information retrieval interface 16 permits retrieval of informationitems 20 dynamically and independently from the categorization of theinformation items 20 based on the categories definitions 24. Theinterface 16 may be embodied to allow information item retrieval to beperformed directly or indirectly by a user, for example in an embodimentwhere the disclosed system stores personal information for that user.Such user controlled actions may, for example, be provided by throughgraphical user interface (GUI) or the like associated with or providedby the interface 16, and/or provided by one of the applications 18.Information item retrieval through the interface 16 is accomplished in apreferred embodiment based on input information retrieval queriesincluding one or more category names associated with corresponding onesof the category definitions 24. The information items returned inresponse to such queries reflect the categorization of information items20 based on the ones of category definitions 24 indicated by thecategory names contained in such queries. The interface 16 may beembodied such that any specific query language, including but notlimited to SQL (Structured Query Language) or extensions of SQL, or thelike, may be used to indicate the information items to be retrieved. Theinterface 16 may also or alternatively allow information item retrievalby software programs and/or processes external to the data storage andretrieval kernel 12. Such actions may, for example, be provided throughan application programming interface (API) or the like associated withor provided by the interface 16.

FIG. 2 is a flow chart illustrating steps performed to accomplishcategory family registration in an illustrative embodiment. The steps ofFIG. 5 may, for example, be performed by the data storage and retrievalkernel 12 of FIG. 1, in response to creation, receipt, modification ordeletion of an information item category through the information itemand category creation and modification interface 14.

At step 40, the disclosed system obtains a parameterized categorydefinition, for example in the form of a parameterized predicate. Atstep 42, the parameterized category definition is processed as needed sothat the parameterized part and the remaining static, part can beconveniently identified. For example, the parameterized categorydefinition may be processed at step 42 by conversion to a logicalorganization such as conjunctive normal form. As it is generally known,a logic statement is in conjunctive normal form if it is a conjunction(sequence of logical ANDs) consisting of one or more conjuncts, each ofwhich is a disjunction (logical OR) of one or more literals (i.e.,statement letters and negations of statement letters). Examples ofconjunctive normal form statements include:

(A OR B) AND ((NOT A) OR C)

A OR B

A AND (B OR C)

Such a conversion may be useful to organize the parameterized categorydefinition so that at step 44 it can be split into a separateparameterized part and remaining static part. Based on the splitperformed at step 44, the disclosed system performs processing on theparameterized and static parts. At step 46, the disclosed systemprocesses the static part of the parameterized predicate by creatingassociations between a name for the family of categories and informationitems that match the static part of the parameterized categorydefinition. These associations define a set of information itemsassociated with the family of categories. With regard to theparameterized part of the parameterized category definition, at step 48the disclosed system analyzes it to determine the specific parametersfor which values will subsequently be provided to dynamically determinecategory membership. At step 50, the disclosed system generates indicesreflecting the parameterized part that are used to speed up subsequentsearches. In this regard, within step 50, a set of existing index datastructures are searched for any that match one or more of the parametersin the parameterized part of the category family definition. Forexample, if the parameterized part of the category family definitionincludes start time and end time parameters, then the search at step 50would be for any existing index data structures mapping informationitems having start time or end time properties to specific start time orend time values. Any existing indices matching the parameters in theparameterized part are then associated with the name of the family ofcategories for subsequent use in processing queries. In this way thedisclosed system provides for sharing of indices across families ofcategories that have portions of their parameterized categorydefinitions in common.

If there are portions of the parameterized part that do not match anyexisting indices, at step 50 the disclosed system creates the necessaryindices. For example, those information items associated with thecategory of families using the static part of the parameterized categorydefinition may be indexed based on some or all of the parameterized partof the parameterized category definition to form such necessary indices.In this way, the disclosed system may avoid indexing the complete set ofall existing information items to form such necessary indices.

FIG. 3 is a flow chart illustrating steps performed to process a queryusing category families in an illustrative embodiment. For example, thesteps of FIG. 3 may be performed by the data storage and retrievalkernel 12 in response to a search query including a category family nameand parameter values through the information retrieval interface 16. Atstep 60, the disclosed system obtains the search query including acategory family indication, such as a category family name, andparameter values for identifying a specific category within that familyof categories. For example, a query might indicate the family ofcategories for appointments having a name “Appointments”, and indicate astart time parameter value indicating a first day and time, and an endtime parameter value indicating a second day and time. At step 62, thedisclosed system uses the parameters obtained at step 60 with the indexdata structures associated with the family of categories to identify andlist information items that are members of a “virtual” category familydynamically defined within the family of categories by the parametervalues provided in the search query. For example, the disclosed systemmight generate a list all information items representing Appointmentsthat are scheduled between the first day and time and the second day andtime parameter values. At step 64, the list of information itemsgenerated at step 62 is restricted according to any other queryconditions within the query obtained at step 60. For example, theinformation items listed at step 62 may be reduced to the set ofAppointment information items within the specified time range, and onlyrelating to a specific subject matter also indicated in the queryobtained at step 60.

Those skilled in the art will recognize that the disclosed system may beembodied in various specific ways to provide many significantadvantages. First, any application may operate using or based on thedynamic categorizations provided by the disclosed system. For example,in one embodiment, a search application or tool may operate to performsearches and apply rankings of the search results based oncategorizations of information items provided by the disclosed system.In such an embodiment the search tool might respond to a search query bysearching only for information items belonging to some combination ofcategories defined by the category definitions 24 of FIG. 1.

Additionally, any specific intensional definition can be used in thepredicates for the category definitions of the disclosed system. Forexample, a predicate may test an information item for the existence inan information item of all properties in a set of one or moreproperties. Or, a predicate may test an information item for thepresence of at least one property within a set of properties. Anothertype of predicate may test the cardinality of certain properties. Such apredicate may test whether an information has a specific property, andwhether the information item has some predetermined number of values forthat property. If the information item does not have the predeterminednumber of values for the property, then such a predicate is notsatisfied.

The disclosed system may further include value-based predicates, whichtest for certain property values. Value-based predicates may test anyspecific property for any specific value. For example, these predicatesmay test whether a Boolean property has a true or a false value, whethera zip code property has a certain zip code value, whether a priceproperty has a value between a minimum and a maximum price, whether adate property is between a starting date and an ending date, etc.

Another type of predicate that may be used in an embodiment of thedisclosed system tests one or more referential properties of aninformation item. These predicates test whether a value of a property isa reference (e.g. pointer) to another information item belonging to aspecified category or set of categories.

The above described predicate examples are given for purposes ofexplanation only, and those skilled in the art will recognize that thedisclosed system is not limited to those specific types of predicates,and that other types of predicates may readily be used in thealternative or additionally.

FIGS. 1-3 are block diagram and flowchart illustrations of methods,apparatus(s) and computer program products according to an embodiment ofthe invention. It will be understood that each block of FIGS. 1-3, andcombinations of these blocks, can be implemented by computer programinstructions. These computer program instructions may be loaded onto acomputer or other programmable data processing apparatus to produce amachine, such that the instructions which execute on the computer orother programmable data processing apparatus create means forimplementing the functions specified in the block or blocks. Thesecomputer program instructions may also be stored in a computer-readablememory that can direct a computer or other programmable data processingapparatus to function in a particular manner, such that the instructionsstored in the computer-readable memory produce an article of manufactureincluding instruction means which implement the function specified inthe block or blocks. The computer program instructions may also beloaded onto a computer or other programmable data processing apparatusto cause a series of operational steps to be performed on the computeror other programmable apparatus to produce a computer implementedprocess such that the instructions which execute on the computer orother programmable apparatus provide steps for implementing thefunctions specified in the block or blocks.

Those skilled in the art should readily appreciate that programsdefining the functions of the present invention can be delivered to acomputer in many forms; including, but not limited to: (a) informationpermanently stored on non-writable storage media (e.g. read only memorydevices within a computer such as ROM or CD-ROM disks readable by acomputer I/O attachment); (b) information alterably stored on writablestorage media (e.g. floppy disks and hard drives); or (c) informationconveyed to a computer through communication media for example usingwireless, baseband signaling or broadband signaling techniques,including carrier wave signaling techniques, such as over computer ortelephone networks via a modem.

While the invention is described through the above exemplaryembodiments, it will be understood by those of ordinary skill in the artthat modification to and variation of the illustrated embodiments may bemade without departing from the inventive concepts herein disclosed.Moreover, while the preferred embodiments are described in connectionwith various illustrative program command structures, one skilled in theart will recognize that they may be embodied using a variety of specificcommand structures. Accordingly, the invention should not be viewed aslimited except by the scope and spirit of the appended claims.

1. A method of providing categories for information items stored in aninformation storage and retrieval system, comprising: obtaining aparameterized category definition for a family of categories; logicallyseparating a parameterized part of said parameterized categorydefinition from a static part of said parameterized category definition;associating those of said information items matching said static part ofsaid parameterized category definition with said family of categories;generating at least one search index associating those of saidinformation items associated with said family of categories and havingproperties matching said parameterized part of said parameterizedcategory definition with parameter values for said parameterized part ofsaid parameterized category definition; obtaining a search queryincluding an indication of said family of categories and parametervalues for said parameterized part; and determining, responsive to saidindication of said family of categories, said parameter values of saidparameterized part, and said at least one search index, which of saidinformation items match said search query.
 2. The method of claim 1,wherein said generating said at least one search index comprisesidentifying one or more existing search indices matching at least aportion of said parameterized part of said parameterized categorydefinition and sharing said existing search indices with another familyof categories.
 3. The method of claim 1, wherein said generating said atleast one search index comprises dynamically creating at least one indexby, at least in part, indexing said information items associated withsaid family of categories to determine which of said information itemsassociated with said family of categories match said parameterized partof said parameterized category definition.
 4. The method of claim 1,wherein said obtaining said parameterized category definition comprisesobtaining said parameterized family definition at run time from aseparate application program.
 5. The method of claim 1, wherein saidparameterized category definition comprises a parameterized predicate,wherein said parameterized predicate, in combination with a set ofdynamically obtained parameter values for said parameterized part,provides a test for an information item to which said parameterizedpredicate is applied, the result of which indicates whether saidinformation item is a member of a dynamically defined category definedby said category family definition and said parameter values.
 6. Themethod of claim 1, further comprising: converting said parameterizedpredicate into a conjunctive normal form logical representation; anddividing said parameterized predicate into a static part and aparameterized part.
 7. A system including a computer readable medium,said computer readable medium having a computer program stored thereonfor providing categories for information items stored in an informationstorage and retrieval system, said computer program comprising: programcode for obtaining a parameterized category definition for a family ofcategories; program code for logically separating a parameterized partof said parameterized category definition from a static part of saidparameterized category definition; program code for associating those ofsaid information items matching said static part of said parameterizedcategory definition with said family of categories; program code forgenerating at least one search index associating those of saidinformation items associated with said family of categories and havingproperties matching said parameterized part of said parameterizedcategory definition with parameter values for said parameterized part ofsaid parameterized category definition; program code for obtaining asearch query including an indication of said family of categories andparameter values for said parameterized part; and program code fordetermining, responsive to said indication of said family of categories,said parameter values of said parameterized part, and said at least onesearch index, which of said information items match said search query.8. The system of claim 7, wherein said program code for generating saidat least one search index comprises: program code for identifying one ormore existing search indices matching at least a portion of saidparameterized part of said parameterized category definition; andprogram code for sharing said existing search indices with anotherfamily of categories.
 9. The system of claim 7, wherein said programcode for generating said at least one search index comprises programcode for dynamically creating at least one index by, at least in part,indexing said information items associated with said family ofcategories to determine which of said information items associated withsaid family of categories match said parameterized part of saidparameterized category definition.
 10. The system of claim 7, whereinsaid program code for obtaining said parameterized category definitioncomprises program code for obtaining said parameterized familydefinition at run time from a separate application program.
 11. Thesystem of claim 7, wherein said parameterized category definitioncomprises a parameterized predicate, wherein said parameterizedpredicate, in combination with a set of dynamically obtained parametervalues for said parameterized part, provides a test for an informationitem to which said parameterized predicate is applied, the result ofwhich indicates whether said information item is a member of adynamically defined category defined by said category family definitionand said parameter values.
 12. The system of claim 7, furthercomprising: program code for converting said parameterized predicateinto a conjunctive normal form logical representation; and program codefor dividing said parameterized predicate into a static part and aparameterized part.
 13. A computer program product including a computerreadable medium, said computer readable medium having stored thereon acomputer program for providing categories for information items storedin an information storage and retrieval system, said computer programcomprising: program code for obtaining a parameterized categorydefinition for a family of categories; program code for logicallyseparating a parameterized part of said parameterized categorydefinition from a static part of said parameterized category definition;program code for associating those of said information items matchingsaid static part of said parameterized category definition with saidfamily of categories; program code for generating at least one searchindex associating those of said information items associated with saidfamily of categories and having properties matching said parameterizedpart of said parameterized category definition with parameter values forsaid parameterized part of said parameterized category definition;program code for obtaining a search query including an indication ofsaid family of categories and parameter values for said parameterizedpart; and program code for determining, responsive to said indication ofsaid family of categories, said parameter values of said parameterizedpart, and said at least one search index, which of said informationitems match said search query.
 14. A computer data signal embodied in acarrier wave, said computer data signal including at least one computerprogram for providing categories for information items stored in aninformation storage and retrieval system, said computer programcomprising: program code for obtaining a parameterized categorydefinition for a family of categories; program code for logicallyseparating a parameterized part of said parameterized categorydefinition from a static part of said parameterized category definition;program code for associating those of said information items matchingsaid static part of said parameterized category definition with saidfamily of categories; program code for generating at least one searchindex associating those of said information items associated with saidfamily of categories and having properties matching said parameterizedpart of said parameterized category definition with parameter values forsaid parameterized part of said parameterized category definition;program code for obtaining a search query including an indication ofsaid family of categories and parameter values for said parameterizedpart; and program code for determining, responsive to said indication ofsaid family of categories, said parameter values of said parameterizedpart, and said at least one search index, which of said informationitems match said search query.
 15. A system for providing categories forinformation items stored in an information storage and retrieval system,said computer program comprising: program code for obtaining aparameterized category definition for a family of categories; means forlogically separating a parameterized part of said parameterized categorydefinition from a static part of said parameterized category definition;means for associating those of said information items matching saidstatic part of said parameterized category definition with said familyof categories; means for generating at least one search indexassociating those of said information items associated with said familyof categories and having properties matching said parameterized part ofsaid parameterized category definition with parameter values for saidparameterized part of said parameterized category definition; means forobtaining a search query including an indication of said family ofcategories and parameter values for said parameterized part; and meansfor determining, responsive to said indication of said family ofcategories, said parameter values of said parameterized part, and saidat least one search index, which of said information items match saidsearch query.